5,718 research outputs found
Exploring wind direction and SO2 concentration by circular-linear density estimation
The study of environmental problems usually requires the description of
variables with different nature and the assessment of relations between them.
In this work, an algorithm for flexible estimation of the joint density for a
circular-linear variable is proposed. The method is applied for exploring the
relation between wind direction and SO2 concentration in a monitoring station
close to a power plant located in Galicia (NW-Spain), in order to compare the
effectiveness of precautionary measures for pollutants reduction in two
different years.Comment: 17 pages, 7 figures, 2 table
Statistical analysis on high-dimensional spheres and shape spaces
We consider the statistical analysis of data on high-dimensional spheres and
shape spaces. The work is of particular relevance to applications where
high-dimensional data are available--a commonly encountered situation in many
disciplines. First the uniform measure on the infinite-dimensional sphere is
reviewed, together with connections with Wiener measure. We then discuss
densities of Gaussian measures with respect to Wiener measure. Some nonuniform
distributions on infinite-dimensional spheres and shape spaces are introduced,
and special cases which have important practical consequences are considered.
We focus on the high-dimensional real and complex Bingham, uniform, von
Mises-Fisher, Fisher-Bingham and the real and complex Watson distributions.
Asymptotic distributions in the cases where dimension and sample size are large
are discussed. Approximations for practical maximum likelihood based inference
are considered, and in particular we discuss an application to brain shape
modeling.Comment: Published at http://dx.doi.org/10.1214/009053605000000264 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
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